How much oil does the 2014 GMC Yukon take?

The 2019 GMC Yukon has the capacity of 6 quarts of oil, which includes replacing the filter, so You'll need to buy an additional quart if You go with a gallon jug. You should fill with a synthetic blend, which will contain seal conditioners to prevent leaks; not a concern in a vehicle as new as Yours is yet, but it will be down the road, so starting now means less problems later. For the viscosity, You're going to want to follow GM's that You use A5W-30, though if You're driving where it often gets lower than 20 degrees below zero, You should change this out for a 0W-30. If You're changing the oil Yourself, don't put more than 18 pound feet of torque on the oil drain plug when You tighten it back up.